Making crabapple butter and jelly

I have a large crabapple tree in my yard that can yield up to 70 pounds of ripe crab apples.  I try to use as much of the fruit as I can to make crabapple butter and jelly.  It is tasty stuff, and I often sell jars of it to my airbnb guests.

I begin by laying out a large tarp under the tree and then shake the branches vigorously using a long extendable pole with a hook on the end:

Then comes the process of sorting the good fruit from damaged or bug infested apples, here is my friend Alison helping me with that step:

This results in a bucket filled with good clean, ripe crabapples weighing up to 20 pounds:

In the kitchen I weigh out around 10 pounds of crabapples and cut the ends off each one and boil them in a large pot until they are mushy.  If I am making crabapple butter, the mush is strained through a press to eliminate seeds and skins etc.  Or, if I am making jelly, I dump it into a cheesecloth lined strainer to drain the juices out overnight:

The resulting juice or clarified mash is then boiled in a pot with an equal amount of sugar and additional spices like cinnamon, thyme, allspice etc.  I use raw sugar rather than refined white sugar:

Since crabapples have a fair amount of pectin in them, there is no need to add it in order to get the jelly or jam to set up.

The final step is canning in which the hot juice is poured into sterilized glass jars and set aside to cool:

10 pounds of crab apples will yield a dozen or so jars of butter, or eight or nine jars of jelly:

The whole process can take over six hours from shaking the tree to finished jam, but it's worth it!  I am often complimented on how tasty my jams and jellies are.

I try to make best use of all the natural resources available on my property.  My raised vegetable beds have yielded a good crop of sugar snap peas, cherry tomatoes, basil, rhubarb, and some other herbs and spices.  I also use responsible forestry management techniques to harvest trees from the woods behind my house for firewood to heat my workshop. (here is my blog post about that). 
 

Decentralised mini-grids based on renewable energy

 - Reducing emissions of offshore oil&gas platforms by installing wind power based mini-grids

PhD stud. Valerie-Marie Kumer, Geophysical Institute, University of Bergen, PhD stud. Pål Preede Revheim, Department of Engineering, University of Agder, PhD stud. Til Kristian Vrana, Department of Electric Power Engineering, The Norwegian University of Science and Technology (NTNU)

Introduction

Gas turbines are used for electricity production on offshore oil&gas platforms all over the world. These gas turbines account for a significant share of Norway's total CO2 emissions. The nice 'fact' of Norwegian electricity production being 98% hydro power, which is cited everywhere and all the time, is simply not true, as all those electricity generating offshore gas turbines are located in the Norwegian part of the North Sea and therefore in Norway. Due to these facts has the oil&gas industry been obliged by the Norwegian government to reduce CO2 emissions.

A first 'solution' to the problem has been a cable connection to shore, to avoid the need for the offshore gas turbines. From a local point of view, this is a solution as there is no more emissions directly from the platform. Global warming is however not a local problem. From a global point of view, this 'solution' is mostly a hoax, as the consumed electricity has to be produced somewhere else onshore. To supply the platform by clean and green Norwegian hydro power is a myth. The additional onshore electricity demand is covered by the marginal production units, which at the moment mostly are hard coal and gas fired power plants. Therefore can the grid connection of offshore oil&gas platforms not lead to a reduction of CO2 emissions. It only leads to a relocation, which has no significance.

A real solution would be to install renewable generation units in proximity of the oil&gas platform, that can partly cover the electricity demand and therefore lead to a reduction in fuel consumption of the gas turbines. The combined system of the oil&gas platform and the renewable generation units would form a so-called decentralised mini-grid.

To realise such a mini-grid, there are several renewable electricity generation technologies available, but most of them are not suitable for the implementation offshore. Photovoltaic systems need a large area. The supply of an oil&gas platform needs two orders of magnitude more electricity, than a photovoltaic system on the platform could generate. There is also little experience with the application of solar panels in hard salty offshore conditions. Wave and tidal electricity generation would of course be a nice option offshore, but those technologies are still in the early phase of development and not available for industrial application. This leaves wind power to be the only realistic solution for this purpose. We therefore propose a wind power based mini-grid as power supply for future oil&gas platforms.

Proposal

As an illustrative example we use the oil&gas platform Valhall in the North Sea, which has a maximum electricity demand of 78 MW. For power supply, the platform is connected to the onshore grid with a power cable of 292 km length. The expenses of such a cable are very high, and it does not help to reduce the global CO2 emissions.

For future oil&gas platforms, a wind power based mini-grid should be considered instead. To reduce the fuel consumption of the offshore gas turbines, we would construct an offshore wind park of 15 turbines with 5MW capacity each. To choose a suitable wind turbine design, layout and location, we analysed wind data from the Heimdal platform. We do not have wind data from Valhall, but the regional differences within the North Sea are limited, and therefore the Heimdal data should be to some extend representative for Valhall as well.

Figure 1. Mean wind speeds and max. gust at the Heimdal platform

As the wind power production is not constant, the gas turbines will produce electricity in the range of 3 to 78 MW. Depending on the weather condition, some gas turbines could be switched off or run on reduced power. Switching off all gas turbines is not a viable solution, as they are needed for power regulation and to provide the platform with e.g. heating. This implies the installation of an intelligent power regulation system, to account for wind fluctuations.

Figure 2. Cumulative expected wind power production as share of the installed capacity

The daily maintenance of the wind power plant could be performed by the technical staff at the oil&gas platform if trained appropriately.

Realising this approach would cover 44% of the over all electricity demand. This would lead to a significant reduction of GHG emissions, which would be a huge and attractive step in reaching future emission goals.

Pushing the boundaries

We could even go further than 44% electricity demand by increasing wind power capacity. If we would install 165MW we would achieve an average production of 78 MW. However, this would lead to overproduction and therefore energy loss, in strong wind cases for 45% of the time. Therefore, an introducing of innovative energy storage facilities would be of great profit.

To increase the share of RES without risking wasting electricity we would need to include some sort of storage solution. As the electricity consumption of the system is high and the periods with over- or underproduction of wind power must be expected to last for periods of multiple days at a time, the storage capacity would need to be relatively large.

The most mature large capacity storage solution is at the moment pump-hydro. This however requires some height difference between an upper and a lower reservoir, which is difficult to achieve in the middle of the North-Sea. Even though some very innovative solutions with inflatable reservoirs creating a few meters of height difference have been proposed, we consider pump-hydro as out of the question as a storage solution for off-shore wind power.

Battery storage is another rather mature technology, but this however has the disadvantage of being heavy and space-demanding. One solution will be to install batteries in the base of the towers of the wind turbines. This will solve the space and weight problem, but it will create challenges with regards to maintenance and durability as the design lifetime of the wind turbines by far exceed that of the batteries and replacement of large batteries encapsulated in the towers will be impossible. All in all we consider batteries to be an unrealistic storage solution for this purpose.

Hydrogen storage would also be an option, and it might have the advantage that the hydrogen could be used in the turbines already on the platform, thus reducing the need for new electricity generating equipment. Operational experience have however shown that hydrogen storage solutions have had a low efficiency and high maintenance requirements,  which is a serious disadvantage for this purpose.

Compressed air storage is a relatively new technology for large scale energy storage, but it has a high potential where one has some natural reservoir for the compressed air. At an oil&gas platform we will have two options for air storage, either the legs of the platform or empty oil&gas reservoirs. To supplement the compressed air storage we propose to include flywheels in the base of the wind turbine towers. These will help smooth out high frequency fluctuations making the system more reliable and help save maintenance. Compared to batteries, flywheels has the advantage that they are less subject of load-unload cycle tear and wear.

Conclusion

There are large plans for the installation of offshore wind power plants in the North Sea, with long cables to transfer the produced electricity to shore. At the same time long cables are installed to supply power from shore to oil&gas platforms. It would be highly beneficial to integrate offshore wind power plants and oil&gas platforms together to form offshore mini-grids instead of sending power over long distances to shore and back. This would lead to less long distance electric power transmission (fewer expensive cables, less electric  losses) and to CO2 emission reductions of the offshore oil&gas platforms.

Without storage, up to 44% of the power supply could be implemented with offshore wind power plants. To increase the renewable share beyond that will call for more complex system design including electric energy storage.

Energigjenvinning av avløpsvann

Av Tor Haakon Bakken, PhD-student ved CEDREN

Anslag fra NVE, Vestlandsforskning, SSB antyder at 10-20 % av energiforbruket i en vanlig norsk husholdning går til oppvarming av vann i varmtvannsbereder, og ytterligere energi går til oppvarming av vann i vaskemaskin, oppvaskmaskin og i forbindelse med matlaging. Det totale energiforbruket til oppvarming av vann kan anslagsvis være 25 % av det totale energiforbruket (som regel elektrisitet) og internasjonale anslag ligger prosentvis enda høyere. Det aller meste av dette vannet sendes rett i sluket og ut på det kommunale avløpsnettet med mye gjenværende energi (i form av varme).

Ideen går ut på å ta vare på denne varmen i avløpsvannet og bruke denne til ny oppvarming av rent vann, evt. til oppvarming av rom i hus. Ideen er å utvikle et system som automatisk skiller varmt fra kaldt vann i avløpssystemet i huset, dvs. før vannet slippes ut på stikkledning og ‘tappe’ energien i det varme vannet gjennom (for eksempel til oppvarming av varmtvannsbereder eller rom) før det avkjølte vannet slippes tilbake til avløpsledningen og ut sammen med det kalde vannet. En realisering av ideen kan være å installere en sensor høyt opp i de av rørene som frakter varmt og kaldt vann for å detektere temperaturen i vannet. Når vannet holder en temperatur som er høyere enn en bestemt grenseverdi ledes vannet inn i et eget rør hvor vannet midlertidig sluses inn i et separat system hvor varmen i vannet tappes. Energien i det varme vannet kan for eksempel brukes til å varme opp varmtvannsbereder. Den kan benyttes en varmeveksler, være direkte kontakt mellom varme/kalde overflater eller lignende. Når vannet er tappet for varme ledes vannet tilbake til avløpsledningen der det kalde vannet renner ut av huset og ute i gata sammen med det andre avløpsvannet. Varme gjenvinnes dermed internt i huset før det slippes ut sammen med annet avløpsvann/gråvann. 

Det later til å være flere mer eller mindre ferdige tekniske konsepter som kan anvendes til dette, og min vurdering er at det er ikke behov for krevende teknisk utvikling for å realisere konseptet. Det finnes blant annet piloter i Hamburg, det er gjort forskning i Nederland og Husbanken har faktisk beskrevet et konsept som virker mer eller mindre klar til anvendelse, med noen forskjeller fra hva jeg tenker. 

I en innovasjonssammenheng er det imidlertid interessant å spørre seg hvorfor dette ikke i større grad er tatt i bruk og det er kanskje der arbeidet burde gå videre. Spørsmål som bør stilles er hvorvidt det er økonomiske eller institusjonelle barrierer som stenger for anvendelsen. Er rammevilkårene gode nok, eller ville en subsidiering på lik linje med den støttet ny el-produksjon (ref. grønne sertifikater) får gjøre at varmegjenvinning vil "av seg selv" og komme i anvendelse? Finnes det en leverandørindustri som er klar? Slike spørsmål bør besvares for å berede grunnen for «det neste store ENØK-tiltak i norske boliger».

Tor Haakon Bakken

Partial solar eclipse and solar output

Maine photographer Mike Leonard drove to Illinois to capture the image above of the total eclipse today (August 21, 2020).  Here along the Maine coast we saw a partial (50-60%) eclipse.  It definitely got noticeably darker and cooler and impacted my solar power output.

The chart above came from my Weather Underground personal web page, there's a clear dip in solar Watts.

Looking at the past 5 days of the power output of my solar power system, you clearly see the correlation as the eclipse occurred today.

Zooming in it becomes even clearer.  Utilities that rely on large solar farms need to plan ahead for an eclipse by having their peaking generators on standby.  These are typically natural gas or hydro generators that are nimble enough to be able to ramp up their output rapidly.

I have a single 245W solar panel on the south wall of my house that also shows the power drop.

It was also interesting to feel the temperature drop.  The change was palpable when I was outside.

So that's how a solar energy geek experiences a solar eclipse!  The next full eclipse in the US will be on April 8, 2024 and we should get a nearly full eclipse in Maine.

Vi i Morpho Solar er en spinoff-bedrift fra NTNU sin entreprenørskole som utvikler innovative varmelagre for solkjøkken. Teknologien vi har muliggjør lagring av solvarme i flere timer.

Solkjøkken er nytt i Norge, men er allerede kjent i USA og en rekke land i Asia og Afrika. Solkjøkken er en slags blanding av en utegrill og et stormkjøkken, men varmen kommer direkte fra solen. Solstråler blir konsentrert ved hjelp av speil, og varmen kan brukes direkte til matlaging. Vi utvikler et termisk varmelager som stabiliserer solkjøkken og gjør det mulig å også bruke solkjøkken på kvelden og når det skyer over.

 

 

Verdensledende forskning fra NTNU

Forskningen har vært et samarbeidsprosjekt mellom NTNU og seks afrikanske universitet, med god støtte fra Forskningsrådets NORGLOBAL-program. Forskningsmiljøet ved Energi- og prosessteknikk ved NTNU har jobbet med dette i flere år og har kommet fram til verdensledende forskning. Professor Ole Jørgen Nydal og doktorgradsstipendiat Asfafaw H.Tesay har stått sentralt i utviklingen av teknologien.

Vi i Morpho Solar har vært i både USA, Etiopia og India for å undersøke markedet, og vi vet nå at dette er verdensledende teknologi. Det finnes ikke lignende løsninger på markedet, men behovet er stort og vi har allerede flere interesserte kunder.

Fra Europa til verden

Det er et stort behov for bærekraftige energikilder for matlaging i verden. Vi i Morhpo Solar har som mål å gi miljøvennlige og trygge matlagingsløsninger til utviklingsland, og ønsker å forandre verden med teknologien. For å få produktet ut på markedet vil vi begynne i markeder som vi kjenner til, nemlig i Skandinavia og i Europa. Ved å vise at det fungerer her vil det være enklere å utvidere til utviklingsland om noen år. I disse landene vil stabile solkjøkken bidra til å løse utfordringer knyttet til miljø, avskoging og helseproblemer som oppstår ved matlaging.

Vi vil begynne å selge solkjøkken i Norge allerede neste år, og har store ambisjoner om å få nordmenn ut i sola og lage mat med solvarmen. Det er gøy, sosialt og miljøvennlig å lage mat på solkjøkken, og nordmenn kan glede seg til å gjøre dette neste sommer.

 

Daglig leder Guro Grytli Seim (til høyre) lager mat på solkjøkkenet som vil være til salgs i Norge neste år.

Det at vi fikk Grønn Fases energipris er en vanvittig motivasjonsfaktor for oss. Pengene vil bli brukt til produktutvikling slik at vi klarer å lage et best mulig produkt. Teknologien fra NTNU fungerer, men vi må tilpasse den for å lage et perfekt solkjøkken. 

Olje- og energiminister Tord Lien overrekker Grønn Fases energipris til markedssjef Even Haug Larasen (til venstre).