Even with energy prices temporarily on the wane there is still a substantial desire amongst many companies to go green and reduce their non-renewable energy usage to the extent practicable within good business practices. In other words, an investment in alternative energy sources still has to be a good investment. With sales slow in so many industries (not just the radio industry) now is a good time to be a buyer; and since energy prices are bound to rise with the end of the recession, the best time to invest in alternate energy may be now. Waiting til energy prices rise will surely give an advantage back to the sellers, thus diminishing the potential ROI.
This is not an article about getting off of the grid though — it's really more about energy conservation. The systems I will mention typically supply on the order of 1kW of power. Unfortunately it just isn't financially viable at this point in time to generate enough power to supply the needs of a 50kW AM transmitter facility (for example). The kinds of systems in this article are grid-connected, and supplant the energy drawn from the ac power grid, at least over part of the day. Solar photovoltaic arrays, wind generators and finally fuel-cells are the types we'll cover.
Solar power and wind power complement one another because usually when the sun is most intense, the wind is weakest; and likewise, it is often windiest when the sun isn't shining. Since broadcasting is a 24-hour-per-day business, our energy needs are mainly constant over the course of the day; but even with wind and solar energy working together, their combined energy output can vary dramatically over 24 hours. For this reason it is often necessary to store excessive energy during the best times of the day, so that the excess can be used by the load during times of the day that the wind or solar power sources are at their weakest. The output of solar arrays is always dc, and used to charge batteries directly. Large inverters are then used to generate ac power for loads that require it. Wind generators come in one of two styles: those that charge batteries, like their solar cell counterparts, or those that have inverters that take dc power from an alternator turned by the blades while the wind is blowing, and then subsequently turn that into ac via an inverter. Usually that type of inverter is connected directly to the line power via a circuit breaker in your ac distribution panel. The inverter synchronizes its frequency and phase, and sets its output voltage accordingly.
Solar arrays can be mounted in many ways and can follow the sun to maximize power with solar trackers.
Even when using wind and solar together, you would likely find times when there was simply not enough energy generated over the course of the day (even with batteries storing energy during the best times of the day) to remove yourself totally from the power grid; for that reason, you may want to consider a means by which you can use non-renewable (or should we call them ‘remnant’) energy sources, such as natural gas or propane, as a third, or backup source of power. That's where fuel-cells come in. We'll get to those a little later.
When using alternative power sources you will want to be as efficient as possible in your energy usage. We've all become a little spoiled with the ac power grid. For the most part you can just keep plugging things in — and the source can handle it. When you start making your own power, you effectively lose that crutch. Your alternative power source will have a limit to what it can do in terms of supply, so you'll need to count your watts carefully.