By Daniel Wamriew, Technology Analyst for Oil&Gas Eurasia
Renewable energy – which you can ultimately say comes from the sun in one way or another – provides opportunities for an unlimited, sustainable energy supply with a low environmental impact. And renewable energy is not just about the future, it is something we can use in our homes today.
True renewable energy sources are energy supplies that are refilled by natural processes at least as fast as we use them. All renewable energy comes, ultimately, from the sun. We can use the sun directly (as in solar heating systems) or indirectly (as in hydroelectric power, wind power, and power from biomass fuels). Renewable energy supplies can become exhausted if we use them faster than they become replenished: most of England’s forests were cut down for fuel before the English started using coal. If used wisely, however, renewable energy supplies can last forever. There are other alternatives to our typical energy sources that are not renewable. Although these are “alternative energy” rather than “renewable energy”, they use the energy we have more efficiently than older technologies. In doing this, they help us make our existing energy supplies last longer and give us more time before we run out of stored fossil and atomic fuels. The use of renewable and alternative energy sources can save us money and assure us that our grandchildren and great grandchildren will have enough energy.
There are many opportunities to generate your own electricity and heat using renewable resources. But first you need to realize that you are making an investment, which can be substantial, and this requires the appropriate research, site considerations, need assessment, and cost effectiveness study. Generating your own electricity and heat may not always make you money or save you money but it can create independence from the utility grid and allow you to generate your own clean and green power. Keep in mind that reducing energy use through conservation and increased efficiency is almost always a cheaper alternative than installing a renewable energy system.
Residential Fuel Cells
Residential fuel cells represent a clean, efficient, nonpolluting source of electrical power. Fuel cells are a renewable energy technology only if their fuel comes from renewable sources, but even if they use fossil-based fuels they use them cleanly and very efficiently.
A residential fuel cell system consists of a fuel processor that converts fuel into hydrogen, a fuel cell stack that converts the hydrogen into direct current electricity, batteries for storing power, and an inverter to produce alternating current.
In a typical fuel cell hydrogen molecules are broken down into negatively charged electrons and positively-charged hydrogen ions at the anode. The electrons flow through the load (delivering power), while the hydrogen ions flow through the electrolyte. At the anode the hydrogen ions and electrons combine with oxygen molecules to form water. Since a single fuel cell has an output of only about one volt, many are combined to form a residential power package.