Virtual Power Plant
Posted 20/11/2012
© Copyright Jikatu and licensed for reuse under this Creative Commons Licence.
By connecting up a range of generation assets and smart grid appliances through the subscription services in homes and businesses we are creating a “virtual power plant” with all the features of a local micro-grid which is capable of starting to net off generation and supply. With the co-operation from our local Distribution Network Operator Scottish and Southern Electricity we will also be able to obtain sight of the loads and flows in some of the pinch points and with one of the most advanced self healing “matrix” like grids in the UK we will be able to distribute the energy over the local grid more evenly – smoothing out flows and hopefully helping to avoid voltage imbalances.
The other feature of our “virtual power plant” structure is that we are building it from the ground floor up. In doing so we have consciously sought to develop a “flexible” load of mixed generation. We need some base load ( Deep Geothermal / Energy from Waste ) some semi-base ( Tidal which though not constant is very predictable ) and then the other renewables ( Solar PV / Wind technology ). Within this there are a number of assets that can be easily controlled. We will also hook up the demand side assets including homes ( where the occupants are happy to subscribe ) small businesses where we hope to have a strong presence by the end of next year and in major plant and other generation on the Island which we will secure under Power Purchase and Export Agreements. The key to the overall solution is to be able to “flex” supply and demand and provide a solution for supply and demand that is not matched.
Generation Mix
Solar PV Residential: There are a large number of solar installations on homes on the Island. We have a total of 65,000 homes and we are hoping to introduce a combination of GreenDeal and ECO-measures, which may give us scope for up to 10,000 home PV installations over a period of 4 or 5 years. There are also 4,000 social houses on the Island that are available for Solar PV installations with the right offer which may come in the hard to treat homes.
Solar PV Commercial: We have a significant number of Commercial Solar Installations on the Island. Most of which are on SME’s some are on large public facilities and others are on agricultural holdings. Together they comprise approximately 30mW of installed capacity.
Solar Thermal: We are deriving a significant amount of benefit from Solar Thermal on the Island. With high degrees of irradiation and well mounted systems solar thermal can produce more than 50% of all the hot water needs of an average house. We have also installed systems in places like Marinas and Swimming pools which have a significant hot water need.
Biomass: There are plans for a large Biomass plant on the Island although there is a challenge in terms of the source of fuel as we only produce about 8,000 tons per annum on the Island and the 50mW plant will require up to 200,000 tons a year. There are a number of opportunities for small biomass plants both for homes and for businesses on the Island.
Anaerobic Digestion: We are working with a consortium of Local Farmers who are working with us to provide up to 17,000 tons of biomass crops a year which will be enough to fuel a 2mW plant. They are “bought into the scheme” with a share of the profits which helps to ensure the continuity of the supply chain. Funding for these schemes is readily available.
Deep Geothermal: Many Islands have major Geothermal Schemes. By drilling down to subterranean watercourses / aquifers you can get to water superheated by the earths core which may output at the surface as steam. These systems don’t only drive Turbines but they can also provide lower grade heat for district heating schemes or other clients i.e. greenhouses for growing vegetables.
Air source / ground source: It is possible to derive heat for OFFgas properties by using the heat in the ground or the air and extracting it via heat exchange ( and compression in the case of air source ) into the hot water system.
Water storage: in a number of properties around the world ( i.e. Canada ) they are using very large water storage under the houses ( up to 40,000 litres ). This can act as a store for surplus renewable energy in the summer months which can then be recovered in the winter.
Small wind technologies: The Windtronic turbines are only 2m in diameter and are highly efficient, working in much lower wind speeds and running up to much higher wind speeds than conventional turbines. With a very quick gust response and capable of withstanding up to 140mph wind speeds they will form the bulk of our wind generation capacity.
Large wind technologies: There is a great deal of speculation about the efficiency of large wind turbines and a great deal of resistance to them in a number of our Communities so we have decided not to press forward with these kinds of installations. Major Marine installations are also hard to service with narrow weather windows for maintenance.
Tidal Center: Tidal energy is one of the most exciting new areas of development. The great thing about tidal streams are they are reliable, often forceful and very predictable making them the ideal companion to other more “volatile” generation technologies. There is a great deal of research into the material science and design of the turbines plus there is a lot of work going into the “anchoring” of these technologies to the ocean floor. There are issues surrounding maintenance, shore-based service centres required to ensure reliability and the licencing of the sea bed but get over that and this may be one of the most successful and least invasive technologies available. There are successful trials of tidal technologies deployed in Scotland and there are new schemes planned for Orkney and Alderney. We have a 20mW tidal R+D site planned on the south side of the Island and the plan, which the IOW Council is leading, is to trial a range of technologies and establish the best after which a full Commercial site of up to 200mW site in a similar location.
Wave technologies: There are a number of wave technologies currently being deployed but they do suffer from considerable inefficiencies, difficulties of wear and tear and maintenance issues. The other issue is that they tend to suffer from the same intermittency ( at a similar time ) to wind technologies as the two sources are inexorably interlinked ( waves being dependent on the wind, duration and fetch ). We do not currently have any plans for the deployment of wave technology because the wavelength here is not very suitable but there are technologies than can be deployed successfully elsewhere in the world.
In stream technology: There are some very effective waterfall technologies based on a flattened water-wheel which can be very efficient and reliable. They can ( with blades that fold on the return cycle be used in tidal locations or estuaries floating on the surface letting water pass underneath. We are deploying a trial of this technology shortly and will report on any findings that we make.
Nano Technology: Some of the greatest new advances in generation technologies will come from nano-tech. Man-made nanoparticles which when combined can form a solar liquid polymer layer which when linked by flat wires to an inverter can cat like solar panels. The polymer is clear and can be sprayed or painted on and with a protective layer can last for up to 20 years at which point it will biograde or you can paint another layer on. With generation capacity of more than 3x the solar PV panels ( restricted to avoid excessive heat generation ) and costs of about 1/3 it could be 10x more cost effective than existing Solar PV. With recipes like the “chartreuse” liqueur living in the mind of the monk ( who I have met ) and the opportunity to mass produce it in vast quantities from a “source” treacle this could be a game changer in the less developed world. Imagine being able to paint the school with the Liquid Solar Layer and use the energy to pump and purify water as well as creating light. It could literally change the world. We have met the scientist and are currently talking to funders to launch the first commercial trial in the UK.
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