Several government officials in the Caribbean region have been promoting renewable energy, particularly wind and photo voltaic (PV) solar, as a panacea for making electricity more affordable in their respective territories.
Indeed, I am aware that in a couple of small islands in the Organisation of Eastern Caribbean States (OECS), ministers of energy are pushing the narrative that their goal is to move away completely from any conventional fossil fuel-based generation and rely solely on wind and solar power and possibly some battery storage.
Unfortunately, this kind of narrative has gained traction with some of their citizenry, the majority of whom are unfamiliar with the hard science and engineering realities pertinent to generation of electrical energy and associated transmission and distribution delivery systems that bring power to homes, commercial establishments and industries.
It always makes me wonder whether the technocrats charged with advising these government officials proffer proper guidance so that these unrealistic narratives are not propagated time and time again.
In the context of our relatively small island electric systems in the Caribbean, the notion that renewable energy is cheap and will lead to lower electricity rates is not entirely true. In fact, there are instances where the case could be made that the cost of renewable penetration may precipitate an increase in rates, albeit with the benefit of lower harmful emissions due to displacement of fossil fuel fired generating assets.
In these parts, unlike in the more developed countries, there are no government subsidies to promote renewable generation. A good parallel is potable water. Just as water is a natural resource, getting clean water to our homes and businesses require a number of intermediate stages – collecting, purifying, pumping and distribution – that involves both significant capital and operational costs. Water utilities in the region are for the most part heavily subsidised by the respective governments to keep the cost to the consumer at a reasonable level.
There is no doubt that renewable energy has a role to play in transforming the energy landscape in the wider Caribbean, given the region’s dependence on fossil fuels – in most cases heavy fuel or diesel. Price volatility of these fuels is a major contributing factor to the high electricity rates in the region.
However, in many of the smaller islands that make up the Caribbean region, there are several limiting factors that inhibit development of renewable generation on a scale that would lead to any significant reduction in electricity rates.
In the smaller Caribbean islands, the lack of suitable real estate, mainly in terms of size and topography, is a key limiting factor in the development of wind and/or PV solar generation of any significant capacity that can influence electric rates.
In Grenada, for example, where the relatively new Electricity Act (2016) makes provisions for creating a competitive market for renewable generation, wind and/or PV solar development would not be possible on a scale that would interest any credible investor. To those who are thinking on a grander scale, I don’t foresee a move to deploy wind turbines in Grenada’s coastal waters now or in the immediate future.
Taking a further closer look at wind and PV solar, there are some territories in the region where utility scale wind and PV solar generation have benefitted utilities by way of displacement of fuel and consequently a reduction in their fuel costs (and the added benefit to the particular country in terms of savings in foreign exchange).
Aruba and Curacao are two examples, each having approximately 30 MW of installed wind capacity, with plans to install more wind generation in the future including PV solar. Both territories are relatively flat and have the available land area for deploying these renewable resources.
Jamaica is another territory where there has been a good level of utility scale wind and PV solar installations – a total of 102 MW of wind and 57 MW of PV solar – majority of which has been developed through a competitive bidding process that was open to Independent Power Producers (IPPs).
This discussion would not be complete without the mention of roof top PV solar installations by residential, commercial, and industrial customers. To date, in most of these islands, such installations have been relatively few and certainly not of sufficient scale to have any real impact on the electric system.
However, there are cases (one example is Barbados with some 28 MW of distributed PV solar), where this conglomeration of distributed PV solar generation would certainly have an effect on the electric system.
By displacing existing conventional generation during unpredictable times of the day, the stability of the electrical grid could be threatened due to lack of inertia (inertia here means stored kinetic energy of the rotating generators) on the system and inadequate ramp rates on conventional generators to respond to the variability inherent in wind and PV solar generating assets.
Maintaining system stability either by having adequate spinning reserve or adding static reactive (VAR) compensation adds to the cost of high renewable penetration and may erase any benefits accrued by way of fuel savings.
With distributed non-firm renewable sources such as wind and PV solar, electric utility system planners must consider the effect on systems such as roof top PV solar during the incidence of a tropical storm or hurricane. By their very nature, these systems are not hardened to the extent that a central facility such as a conventional power plant is reinforced to withstand hurricane force winds or other natural disasters such as earthquakes.
Both electric utility system planners and regulatory agencies must also be cognisant of possible rate inequality (depending on the tariff related to private production of renewable energy) given the fact that roof top PV solar installations are mostly affordable to the more affluent members of the society.
Another renewable resource, geothermal generation, has been heavily promoted in some territories over the last several years, namely in Dominica, Grenada, St. Vincent, and St. Lucia. Development work in these territories has proceeded at a snail’s pace given the enormous capital involved just for exploratory drilling. The majority of the funding for these exploratory works has been by way of grants from friendly governments.
With the possible exception of Dominica, recent attempts at exploration have been either technically inconclusive or of dubious economic feasibility. In the case of Dominica, the geothermal reservoir potential has been estimated to be about 200 MW and the electric utility, DOMLEC, through a newly formed subsidiary company, is seeking offers from developers to construct initially a 10 MW plant with the possibility to further develop the reservoir to facilitate export of power to nearby Guadeloupe.
Recently, there have been some developers pitching waste to energy type generation to some Caribbean islands. The feedstock is of course waste (garbage). One approach being promoted involves a sorting process of the waste and certain components treated to produce a synthetic gas – known in the industry as syngas. The idea is to burn this syngas in a reciprocating engine to produce electricity.
There are two issues with this approach. The first is that to make the venture economically feasible, waste would have to be imported, since as is often the case in these small islands, sufficient garbage is not produced locally. The second is that syngas usually consists of significant proportions of carbon monoxide (CO), carbon dioxide (CO2) and Hydrogen (H2) and it has a relatively low calorific value (heat content) compared to other gaseous fuels. This makes it difficult to burn in high output reciprocating gas fired engines.
I will not elaborate on any mass burn technology for generating electricity from waste as it is certainly not applicable for the region due to reasons of scale and environmental concerns.
The vision to attain 100% renewable generation is a laudable one but that goal must be pursued in a cloak of reality. In our Caribbean region where the most prominent renewable resources are wind and PV solar, utilities are aware that when these resources become part of their generation portfolio, they represent non-firm capacity with outputs varying minute by minute in the most extreme case.
Without resorting to the complex engineering equations relating to stability of the electric system, it is easier to understand that at any given time the power generated must match the load on the system so that the stability of the power grid remains intact (meaning that your home or business will not be subjected to power surges or outages).
This intricate balance is difficult to maintain when sources of generation like wind or PV solar change rapidly, for example, when the wind intensity varies or a cloud causes shadows over the solar panels.
Without a doubt, renewable generation resources such as wind and/or PV solar can be integrated into existing electric systems with proper planning and system modeling. Hybrid systems that comprise renewable generation, conventional generating assets and energy storage systems (using batteries) integrated with an overall computerised energy management system can produce positive results: maximising savings in operating costs and maintaining system voltage and frequency within statutory limits.
In summary, deployment of renewable generation may not always be a least cost generation option for Caribbean electric utilities, but reducing carbon and other emissions harmful to the environment is a good tangential benefit.
Let’s keep in mind that ad hoc installation of wind power and/or PV solar without proper analysis of how the existing electric system will react is setting the stage for possible system instability. And, for those who are currently advocating an “all renewable” based system with only wind, PV solar, and battery storage, well maybe they should have their candles ready.
Rodney George is Vice President Caribbean for Wärtsilä, and is responsible for business development, marketing and sales for the Caribbean region. Wärtsilä with corporate headquarters in Helsinki, Finland, is one of the largest energy companies in the world and is involved in power generation and marine energy systems