GREEN FLASH AT SUNRISE

I saw my first green flash for 2009 a few days ago. Most Caribbean people know what the green flash is. It’s the fleeting change of colour of the last sliver of a setting sun at a clear horizon – from red to green – and it’s gone in an instant.

The (totally exaggerated) green flash depicted in the movie “Pirates of the Caribbean: At World’s End”. The first of the “Pirates” series was filmed in St Vincent & the Grenadines and other Caribbean islands.
Photo: Wikipedia

Later that night, I wondered: is there a green flash at sunrise as well? I’m not a morning person, so I would hardly know. But I figured there should be, since the physics of it (as far as I can tell) would be the same.

In any case, here’s a prediction about solar energy in the Caribbean: sunrise is coming and we’re about to see our green flash. That’s because as oil prices climb back to uncomfortable levels; as energy policy in the Caribbean adjusts to the new global reality; as technology continues to improve and prices continue to fall, electricity generated by photovoltaics will become very popular in these parts.

Photovoltaics (PV) is the name for the process by which light is converted directly to electricity by a solar cell. We’ve got lots of PV-powered devices around already. Look at a pocket calculator. Instead of a battery, it’s got a solar cell on the front that provides the electricity it needs. The same basic technology, on a larger scale and with a few additional devices, is already being used to power homes and businesses worldwide.

A typical home PV system would consist of roof-mounted solar panels, connected to an inverter (a device that converts the direct current produced by the solar panels into an alternating current, which is the same as the electricity that you buy from your electricity company). The inverter is connected via a switch to the main circuit breaker panel that distributes electricity to the house.

So if you had a PV system installed at home: depending on the size of your system, its type (whether it had battery storage or not) and the amount of direct sunlight available at the location, your entire electricity needs could well be supplied from the sun!

This sounds great; so the question is, again (this question will be coming up a lot on this blog): why isn’t more of this renewable energy technology being used in the Caribbean?

There are two basic problems: the first is that the technology is expensive. A PV system of 2.4 peak kilowatts (kWp) capacity, enough to power my own two-occupant home in St Vincent (my electricity demand is pretty low – did I mention I’m an energy efficiency consultant?) could cost up to US$15,000 installed. On the other hand, electricity in these parts is also expensive and we’ve got great sunshine, so I would expect my system to pay for itself in 7 to 10 years or so. After that, I would be making my own electricity – for free.

Essentially, PV works out well on an individual scale, once the matter of the up-front cost can be sorted out. But in the Caribbean, there’s another issue: the utility connection. The best way to use PV is as a grid-connected system. This means that your PV system is connected to the electricity company’s system, so that whenever your system is not producing enough electricity for your needs, the difference comes from the electricity company. At those times when your system is producing more electricity than you need (eg: when it’s a bright sunny day and no one’s at home), the extra energy will actually go into the electricity grid and be used by someone else. You pay for any electricity you use from the grid and the electric company pays you for any electricity your system supplies to the grid. This grid connection and payment arrangement, called “net-metering”, is a well-established practice worldwide.

The problem is that electric utilities generally will not encourage this sort of thing on their own initiative, so what is needed are government policies that encourage customers to invest in PV and laws that require the utilities to work with customers that want to go green. This is exactly what happens in the countries with significant PV use, and what is not happening in the Caribbean – with a couple of exceptions.

Two of the bright spots are found in Grenada and the US Virgin Islands. The utilities in these countries have taken a progressive approach to the matter and as a result the numbers of grid-connected systems are growing nicely (I’ll try to get some actual numbers on this for a future post).

So, the bottom line is there’s no mystery here. PV is not some esoteric, experimental technology that’s not ready for real-world use. It is a well-established (and rapidly-growing) renewable energy technology, in use all over the world, even in not-so-sunny places as Germany and Japan, two of the world’s biggest PV users. We need to use more of it. To do this we need creative ways of dealing with the up-front costs of PV for prospective customers, and we need government policies and net-metering laws, directed at getting the utilities on board.

Meanwhile, PV prices are falling, and sun is shining!

You can find lots of detailed information on PV here http://en.wikipedia.org/wiki/Photovoltaics

SUNNY WITH SHOWERS

The sun is our largest source of energy, but solar energy contributes less than 1% to global energy consumption. In the Caribbean we probably use a similar percentage. In other words: pretty close to zero.

Solar energy in the Caribbean basically refers to two things: solar thermal energy for water heating, and solar photovoltaics (PV) to directly generate electricity from sunlight. Of these, solar thermal easily accounts for the vast majority of our use and our only serious user is Barbados. In fact, Barbados is a world leader in solar thermal energy, as it is estimated that the island has the second highest number per capita of solar water heaters in the world!

Solar water heaters are simple devices that are cheap, effective, easy to install and maintain. And the Caribbean has plenty of the free fuel all year round, so a solar water heater pays for itself quickly, typically in three years or less. So, why is there so little use of solar water heating in the Caribbean? I think the reason is mostly due to a combination of three factors, one economic, one cultural and one related to government policy.

The first is that demand for hot water is higher in richer countries, particularly those with large tourism sectors, but many of the islands of the Caribbean are not quite in that category (yet).

The second is that in some of our countries there is a strongly-held belief that bathing in cold water is intrinsically better for the body. This belief has maintained a demand for cold water even as per capita incomes have increased.

The third factor – government policy – I think is the most important. Faced with several alternatives for doing a particular thing, consumers will not necessarily make the most economic choice. For someone who is building a house, an electric tank water heater priced at $1500 may seem a more attractive proposition than a $3200 solar water heater, never mind that the total cost of the electric heater over ten years will be far greater than that of the solar heater. But if the government provides an incentive for homeowners to spend the extra money up front (and provides some assistance enabling them to do so) then the right economic decision is encouraged.

This sort of government policy intervention has been the missing link in the region thus far.

This is unfortunate, because the fact is whether a country is rich or not, it just makes sense for it to save on its energy import bill by any reasonable means. And what could be more reasonable, in countries where sunshine is clearly abundant, than reducing the consumption of imported diesel fuel by replacing electric water heating with solar? This is no exaggeration: any government that takes this particular matter seriously could make a huge difference – just as the government of Barbados did decades ago.

Barbados, which is relatively rich and with a large tourism sector, got off to an early start with a solar water heating industry dating back to the 1970s (the decade in which the term ‘global energy crisis’ was coined). On the other hand, equally-rich Trinidad & Tobago may well have had significant demand for hot water, but locally-produced oil and gas has made electricity so cheap that no one bothers much what it’s used for.

The basic outline of the Barbados model was summarised in a paper published in 2000 by Professor Oliver Headley, the late dean of solar energy in the Caribbean. He advised that

"A crucial factor in creating the market was the provision of fiscal incentives by the Barbados government under the leadership of (then) Prime Minister Tom Adams. A householder could apply the cost of his water heater against his income tax for the year. The success was remarkable: 23,388 solar water heaters were installed in Barbados over the period from 1974 through 1992."

He goes on to note that

“In terms of avoided imports of fossil energy, the solar water heaters reduce annual imports by 33,000 tonnes of fuel, a saving of about $6.5 million US if one assumes a price of US$25 per barrel. These are the savings that the solar water heater industry achieves for Barbados, with its population of about 260,000. If solar water heating were applied over all the territories of the anglophone Caribbean, with a population of 5 million, to the same extent as in Barbados, savings would be US$125 million per year.”

These are compelling numbers and some Caribbean governments have taken notice, but few (if any) have engaged the matter as seriously as did Barbados’ government. Other incentives can be applied as well. For example: to defray initial costs, banks should be encouraged to automatically finance solar water heaters in new mortgages, and to rewrite existing mortgages to finance replacement of electric heaters.

The above things need to be done – and I believe they eventually will, for the simple reason that rising fossil fuel costs over the long run, coupled with our increasing awareness of the need to reduce carbon emissions, will accelerate adoption of this simple renewable energy technology that is perfectly suited to our region, dependent as it is on tourism for its economic vitality.

But for now, the proverbial rainy day is here. The current global economic crisis is deepening, and will probably get worse for us for a while before it gets better. In the very short term, don’t expect any significant increase in the use of solar energy. As the world emerges from this recession, the use of solar thermal energy in the Caribbean will grow.

What about photovoltaics? We’ll talk about that next week.