Smart Power Grid Combines Batteries, Fuel Cells… And Compost

There are lots of components to the Smart Grid, in which intelligent power technologies combine to provide electricity where we want it, but without the waste associated with the current utility system. But how do they fit together?

Making a more efficient grid that cuts overall energy use involves several things – and tech comes into it at all stages, from better managed batteries, through distributed generation, to smart composting schemes and sensor-based Internet of Things implementations which tune energy use to match the fluctuating power provided by the renewable sources.

The interesting thing is that all the different approaches can add up. Earlier this summer a “CleanTech Club” gathering in London heard how power generation can be distributed to where the power is used, how batteries can smooth the peaks of demand and supply, and how local composting could actually provide a third of the power we use in the home.

A grid that is the sum of its parts?

The CleanTech Club presenters focused on the home or the small office because that is where energy is consumed, and where new initiatives can have most impact. If energy is generated or harvested on site, then it produces more savings than elsewhere, since it eliminates losses in transition.

Home electricity demand is shifting (see the graph in our slideshow below). While lighting has become more efficient thanks to low energy bulbs, the penetration of dishwashers and other gadgets have increased the electricity use in the home, and consumer electronics has sprung from nowhere to become a major power user in the last thirty years.

This shift in usage is one of the issues picked up by Moixa Technology in its proposal for a distributed energy system called Maslow (after psychologist Abraham Maslow’s Hierarchy of Needs).

Moixa’s Maslow is a smart battery which stores energy from a solar panel or other renewable source to be used at night. It’s available in versions which hold 1kWh or 2kWh, is the size of a briefcase, and mounts on the wall.

It’s a master box which can combine grid power with any locally generated electricity, and feed this according to the local requirements of the house, adjusting where possible to match demand and supply. Maslow also provides a clever addition – a  DC distribution system for lighting and gadgets which don’t need AC power. It feeds spare energy back into the mains if there is a surplus (or a beneficial tariff).

A lot of houses in one area can aggregate the energy they store to keep the local grid running smoothly. A £5 million demonstration in Southend on Sea, funded by the Department of Energy and Climate Change, is already showing good results, Moixa CEO Simon Daniel told the event.

Composting and generating

SEAB Energy focuses on the business of extracting energy form local waste – specifically organic matter. This technology is rarely used at the moment, and the energy cost and yuck factor of transporting biomass to composting facilities generally prevents this from happening. But SEAB CEO Sandra Sassow reckons she has the answer: local composting facilities, which her firm sells under the names Muckbuster and Flexibuster.

Sassow reckons we could all cut our electricity bills by composting our organic waste, and a block of 90 flats is a good size for  a local composting unit, which fits in a 20ft wide shipping container. This can actually generate one third of the energy needs of the residents she says – and one interesting fact is that this figure remains roughly constant wherever you go: affluent people discard more material, while poorer people discard more calorific material such as cooking oil, she told TechWeek. “Our approach is 60 percent better than landfill and 30 percent better than shipping waste to a combined heat and power (CHP) facility.”

Even with the use of local solar panels it’s unlikely that many buildings can be self-sufficient in energy, but there are ways to improve the means of supplying energy to houses, said Paddy Thompson of Ceramic Fuel Cells. Instead of using a giant central power station, his firm’s BlueGen is proposing to use millions of fuel cells, each installed in a home. “It’s a power station in the corner of the garage,” he said.

The fuel cell still “burns” natural gas to produce electricity, but doing it on-site has two benefits. Less energy is wasted in transmission, and the waste heat from the generation process can be harnessed to provide hot water for the house.

By coincidence, Thompson reckons his distributed power station approach can cut a third from the consumer’s energy bill – roughly the same as SEAB’s composting proposal.

If these ideas live up to the promise (and let’s remember that green dreams often don’t) then that leaves only a third of the power needs of the home left for the Maslow box to whittle away at.

And further efficiencies can be expected from the UK’s much-maligned smart meter scheme, according to Geo, which provides some of the technology. The UK has insisted that the smart meters involved should be aimed at consumers, rather than the utilities, and provide a screen to explain how energy usage is being improved and made more efficient. “The UK is the only country to go down this route,” he said, arguing that the brave move was the right one.

A final addition to the puzzle is battery storage. While batteries are included in Maslow, Bali Sahdra of AES stepped away from the local solutions other speakers suggested, arguing that even bigger battery installations at the grid scale are needed to match the supply of wind farms to the demand from consumers.

All these elements and others could be added together in a smart grid that really does cut the energy used in homes and small offices, and the amount that has to be shipped around the grid. The end result would be an end to the ever-increasing power demands made on the National Grid, and perhaps a solution to the big problem of creating enough centralised power stations (whether fossil, nuclear or renewable) to meet it.

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